<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>超时与网络异常</title>
</head>
<body>
  <button>点击发送请求</button>
  <button>点击取消请求</button>
</body>
<style>
  #result {
    width: 200px;
    height: 100px;
    border: solid 1px #258;
  }
</style>
<script>
  const btn = document.querySelectorAll('button')
  let xhr = null
  btn[0].onclick = function () {
    xhr = new XMLHttpRequest()
    xhr.open('GET', 'http://127.0.0.1:8000/delay')
    xhr.send()
  }
  btn[1].onclick = function () {
    xhr.abort()
  }
</script>
</html>